Mixtures which include copper ions and an amine are produced in oxidative coupling reactions that are employed to produce polyphenylene oxide resins. Processes for the production of these resins are described in U.S. Pat. No. 3,306,875; U.S. Pat. No. 3,306,875; U.S. Pat. No. 3,639,656; U.S. Pat. No. 3,642,699; U.S. Pat. No. 3,733,299 and U.S. Pat. No. 3,661,848. All of these patents are incorporated herein by reference.
Generally the polymerization processes that are employed to produce polyphenylene oxides result in a complex polymerization mixture which includes polyphenylene oxide polymer, the copper-amine catalyst and the solvent. Various techniques have been employed to isolate the polymer from the reaction mixture including acid extraction of the catalyst, chelation of the catalyst and antisolvent precipitation. Generally, most prior art methods have resulted in a copper containing effluent from which it has been difficult to separate the copper ions. Attempts to use acidic ion exchange resins have been unsuccessful in separating copper ions from mixtures of copper amines. This has been experienced even when the acid ion exchange resin has been saturated with amine prior to extracting of the copper-amine mixture with the acid ion exchange resin. The applicant has discovered that it is possible to separate copper ions from mixtures that include copper and an amine if an acid ion exchange resin is employed in which the acid groups have been replaced with a metal that is above copper in the electromotive series. This process results in a copper containing ion exchange resin that may be regenerated in a two step process with an inorganic acid followed by contact with a metal ion containing solution or with a metal ion chelating agent that exchanges a metal ion above copper in the electromotive series for copper.
Accordingly, it is a primary object of this invention to provide a process for separating copper ions from a mixture that includes an amine.